Two contrasting paths are embraced within the practice of green product development: The first involves market entry with high-quality products in the initial phase, followed by a gradual release of mass-market products at reduced prices. The second entails entering the market with low-quality products, followed by step-by-step improvements in quality. The decision-making on path selection is divided into two stages: in the first stage, firms choose green product technologies, and in the second stage, they determine the path for green product development based on the selected technologies. Our research findings highlight the crucial role of efficiency-cost ratios in product-process innovation for green product development. Equilibriums are only achievable when efficiency-cost ratios are relatively low. Given the singular impact of component cost on profit, the path for process innovation consistently trends downward, whereas the path for product innovation can either descend or ascend. Collaboration positively impacts the conditions for equilibrium existence, making it more attainable. When the manufacturer’s efficiency-cost ratio for product innovation is low, collaboration can transition the path from a descending trend to an ascending one, and vice versa. The selection of appropriate technological parameters is important for achieving a win–win relationship between the environment and profitability. Additionally, we have expanded our models to include competition and marketing scenarios. We find that competition primarily influences green product development by altering the motivation for path selection. Marketing and product-process innovation demonstrate a complementary relationship.